Photosensitive currency testing device



Oct. 29, l96j3 N. A. GECEWICZ PHOTOSENSITIVE CURRENCY TESTING DEVICE Filed May 19. 1960 A C SOURCE INVENTOR. lvorben 4 Gecew/cz United States Patent 3,109,100 PHOTOSENSITIVE CN CY TESTING DEVICE Norbert A. Gecewicz, Rockford, Ill., assignor, by mesne assignments, to Automatic Canteen Company of America, Chicago, 11]., a corporation of Delaware Filed May 19, 1960, Ser. No. 30,275 12 Claims. (Cl. 250-219) This invention relates in general to a material evaluation arrangement and, more particularly, to a currency testing arrangement in which current is automatically accepted, if legitimate, for coin change or other purpose and rejected if simulated or counterfeit, and wherein added test conditions are imposed on the darkest currency areas.

In its organization, the present invention largely comprises novel circuit arrangements for a currency acceptance unit and constitutes an improvement of application Serial No. 744,966, filed on June 6, 1958. That application and its forerunners disclose the mechanical structure and the basic circuit arrangements permitting certain currency evaluations to be made. The arrangement by which this is done comprises a horizontal slide having a trough therein into which currency such as a dollar bill is deposited. A door hingedly secured to the slide is closed over the deposited currency and the slide carrying the currency is reciprocated into a test position between certain lamps and light-responsive cells. On the slide being operated into the test position, appropriate circuitry is controlled to operate a solenoid, which looks the slide in place. The lamps are then lighted. The light is transmitted in various degrees through respective areas of the currency depending, of course, on the color and value of the respective areas. The light-responsive cells underlying the various areas respond to the quantity of light passing through those areas to provide an indication of the-acceptability of the currency. Thus, these cells are divided into three groups called black, white, and green in accordance with the well known characteristics of currency notes. The currency is rejected if either the black or green cells receive more than a predetermined amount of light or the white cells less than a predetermined amount of light. If found unacceptable, the slide is released and coin payout prevented. If found acceptable, the currency is collected into a cash box on being stripped from the slide. This is done by a stripper motor, solenoid and guillotine arrangement which operate as described in the mentioned application. A coin payout motor is now energized and it operates a cam or finger in any well known manner to dispense the required coins. The slide is also released and automatically reciprocated into its nnoperated position where it is prepared to receive another deposit of currency.

In the above-described test, light is passed through various areas of the currency and a determination is made that the black or green areas of the currency transmit less than a predetermined amount of light. Although this arrangement is certainly satisfactory, it leaves an undesirable gap in the adequacy of the test. With the known temptation to produce counterfeit or fraudulent currency, the gap might serve to stimulate the production of counterfeit currency.

It is, therefore, proposed in the present invention to further test the dark areas of the currency for determining that a minimum amount of light passes to indicate that proper or acceptable currency is being tested. This test is performed in addition to the aforementioned test in which the currency does not pass more than a predetermined amount of light, thereby establishing both minimum and maximum values for the amount of light transmission through the dark areas of the currency, whereby the problems of making adequate counterfeit currency for defeating this test apparatus become increasingly difficult.

An object of this invention is therefore the performance of a currency validity test in which the dark areas of a bill, paper money, or a currency note are tested for both minimum and maximum light passage.

It is another object of this invention -to provide for a light passage test in evaluating a material having a plurality of different colors for the maximum light passage through the darkest area.

vit is another object of this invention to provide for the acceptance or rejection of a bill or currency in accordance with the maximum light passed through the darkest areas of a currency note.

It is another object of this invention to provide for the acceptance or rejection of a currency note in accordance with minimum and maximum light values passed through respective colored areas of said note, including the maximum light passed through the darkest area of said note.

With the foregoing, and other objects in View which will appear as the description proceeds, the invention consists of certain novel features of construction, arrangement and a combination of parts hereinafter fully described, illustrated in the accompanying drawing, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportion, size and minor details of the structure and/or circuits may be made without departing from the spirit or sacrificing any of the advantages of the invention.

For the purpose of facilitating an understanding of this invention, there is illustrated in the accompanying drawing a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, this invention, its mode of construction, assembly and operation, and many of its advantages should be readily understood and appreciated.

The drawing illustrates the circuit arrangement whereby the objectives of the present invention are accomplished, and it incorporates with some minor changes the principles disclosed in the aforementioned application.

Referring now to the drawing, there will be seen at the lower left a conventional source of A.C. power 35 connected across a 24-volt transformer 20 via conductors 30 and 32.

Transformer 20 furnishes power to the various test relays comprising the bad impulse relay 170, theblack and white test relays i160 and 150 respectively, and the tray clear test relay 140. In addition, the AC. source 35 is connected to the constant voltage supply, indicated by the box marked 34, for the purpose of ensuring a steady or constant voltage to the various lights 117 and 119.

Lead 30 is also connected to the common ring contacts 101 and 102 carried by the rotor of -a timer motor for selective interconnection with the various leads 40, 41, 42, 43, 44 and 45 to permit the various tests, stripping and coin payout functions to be performed in the proper sequence.

Also connected across the power supply 35 is the primary of transformer 6. Without transformer 6 energized, the rectifier arrangement 12 connected across the secondary of the transformer 6 maintains a constant D.C. braking voltage through contacts 111 on the payout motor 14 to positively prevent its operation until relay is operated.

The empty switch contacts 17. are normally closed if coins are available in the coin dispenser or disposal unit. This extends lead 32 from the empty signal lamp 18 and switches 19 through contacts 21 to lead 30 for energizing s. the lamp. The lamp 18, on energizing, lights to signal the empty condition.

The apparatus further comprises a series of switches 92, 94 and 96, the latter two of which close if the note is properly positioned in the test area. Switch 92 closes in response to the proper positioning of the slide in the test area.

A lock solenoid 125 is provided for locking the slide in position when manually operated into the test area. A stripper motor 145 and stripper solenoid 135 are provided for operating the bill or note-stripping arrangement, including the guillotine, for removing the note from the test area on completion of a successful test.

White, green and black cells 199a, 1991) and 1990 respectively are provided beneath various areas of the bill in the test area and each has associated therewith an individually corresponding meter or galvanometer relay 70, 80 and 85, whose contacts are controlled responsive to the various tests.

A bad impulse relay 170 is operated in the event any validity test except the minimum light tests and the tray clear test are unsuccessful.

In the present arrangement, relay 180 is provided to introduce positive booster battery 166 to the black cells 1990. This permits a determination to be made that at least the minimum amount of light is transmitted through the dark areas of the bill by operating the test relay 150. A similar test is also performed under the control of relay 180 for operating relay 160 under control of the white cells 199a and relay 70.

A tray clear test is performed utilizing certain already described apparatus under control of the relay 190, which is operated responsive to the stripping of the bill from the test area. Relay 191) connects the black cells 1990 across the green relay 80 and the contacts 81 of the green relay 80 to the clear tray test relay 140.

Briefly described, the operation proceeds with the deposit of a currency note, bill or paper in the trough provided in the slide drawer and the manual operation of the slide to the currency-testing position. The lock solenoid 125 is energized responsive to the closure of switches 92, 94 and 96.

If for any reason, such as the improper positioning of the bill or slide, contacts 92, 94 or 96 fail to close, solenoid 125 fails to operate. On release of the manual pressure on the slide, it is then reciprocated to its unoperated position due to the solenoid 125 failing to operate for locking it.

Operation of the lock solenoid 125, on the other hand, completes a circuit to the start relay 120 and that relay initiates operation of the timer motor 109. The timer motor first completes a circuit to the lamps 117 and 119 via contact 101 to light the lamps.

With the slide drawer in its locked operated position, the currency note, bill or paper overlies light-responsive cells 199a, 19% and 199a. These cells underlie respectively hued portions of the currency. Each has associated therewith a respective meter relay 7%, 80 and 85 having respective contacts 71, 81 and 86.

The first test to be performed isan excess of light test. In the case of the white cells 199a, potentiometer or adjustable resistor 198a in circuit with the white cells 199a and the associated relay 70 limits the current therethrough to a predetermined value. It has been the previous practice to test for excess light passing through the black and green cells 19% and 1990 and the addition of this circuit arrangement permits the same function to be performed with the white cells 199a.

Thus, if the current in cells 199a exceeds a predetermined amount, as determined by the setting of resistor 198a, the relay contacts 71 close to place the bad impulse relay 170 across the secondary of transformer 20. Also, in the event either cell groups 19% or 199:: respond to an excess of light passing through the currency, respective relays 80 and 85 close contacts 81 and/ or 86, respectively,

i to place relay 170 across the secondary of transformer 20. With relay 170 across the transformer, it energizes to prevent coin payout, as will be explained.

Assuming that the tests just described were successful and relay 170 was not operated, the progress of timer motor causes contact 102 thereon to complete a circuit to relay 180. Relay 180 now removes potentiometer 198a from the circuit of relay 70 and connects booster battery 166 for the black cell test to determine that suflicient light passes through the corresponding portions of the currency. It also connects the contacts 71 and 86 to the white and black test relays 160 and 150 respectively. Thus, with the proper amount of light passing through the note, cells 199a and 199 cause relays 70 and 85 respectively to close contacts 71 and 86 respectively. tively across the secondary of transformer 20 and each energizes to prepare for operation of the stripper motor 145 and the tray clear test.

The stripper motor 145 is operated by the timer motor 190 providing relays 150 and 160 are operated. It controls the stripper solenoid and the guillotine to strip the currency from the trough in the slide into the proper receptacle. Operation of relay 190 is thereafter provided to permit performance of the tray clear test. Its operation too, of course, is conditioned on the operation of relays 150 and 160 and the failure of the bad impulse relay 170 to operate. Relay 190 may be, of course, operated simultaneously with motor 145 and both may be under control of an intermediate relay, but the test controlled thereby is not performed until the tray is clear.

Relay 190 connects the black cells 19%, across meter relay 80 to provide cells and relay capable of reacting sufiiciently to the light. Contacts 81 of the green cell relay 80 are now connected to the tray clear test relay and responsive to the closure of contacts 81, relay 140 is placed across the secondary of transformer 20 and operates. Of course, if the currency has not been cleared for any reason, insuificient light is transmitted and relay 8% does not energize sufficiently to close contacts 81. If relay 140 is therefore not operated by the time the reset relay 139 is operated, coin payout is prevented.

On completion of the successful clear tray test, relay 140 operates to permit the timer motor 100 to operate relay 110. Relay 1 10 on operation removes the DC. brake on the payout motor 14 and energizes the motor. The payout motor 14- now operates the dispensing finger 14' diagrammatically illustrated for removing the coins to be dispensed from their chute.

The finger 14 of course is operatively connected to the contacts 21, 15 and 16 and if jammed, due to the improper disposition or alignment of one or more coins, it preventsthe contact operation. The further operation of motor 14 is therefore prevented. If the coins are freely disposed, the payout motor 14 and relay 110 are held operated until the coin-disposal cycle is completed.

If, asmentioned previously, the bad impulse relay 170 were operated due to an unsuccessful test, operation of the stripper motor and/ or operation of relay 110* and the payout motor 14 is prevented. Likewise, failure of relays and to operate prevents operation of motor 145, relay 110 and motor 14. If, on the other hand, relay 140 fails to operate while relays 15ft and 160 are operated, the stripper motor 145 is operated, but relay 110 and the payout motor are prevented from operating. in any of these test failure situations, the timer motor 100 operates the reset relay 130, which in turn restores the test components.

In detail, the circuit operation proceeds in the following manner after the currency is inserted in the slide drawer and the slide placed into its operated position with the currency in the test area. The currency feeler This places relays 160 andlSO respecdisposed, in operative relationship to the slide in any well known manner, close responsive to the proper location of the slide in its operated position.

With the slide in its operated position, a circuit is completed from the AC. supply 35 over conductor 32, through lock solenoid -125, through currency feeler contacts 96 and 94, tray feeler switch 92, contacts 131 on reset relay 130, the normally closed empty switch contacts 17, the coin jam contacts 21 and conductor 30 extending to the other side of the AC. supply 35. The lock solenoid 125 energizes in this circuit to lock the slide carrying the currency in its operated position with the currency in the test area and closes contact126.

Contacts 126 on closing connect the conductor 30' ex tending through contacts 132 on reset relay 130, through the winding of start relay 120 to conductor 32 to energize relay 120.

Relay 120 on energizing closes contacts 121 in shunt with contacts 126 to complete a locking circuit for itself. It also closes contacts 122 to connect conductor 30 extending to the timer motor 100. This energizes the timer motor 100. Timer motor 100 now initiates operation of its rotor and the leading finger contact 101 thereon extends power from conductor 30 to conductor 41 to light the scanning lamps 117 and 119. At contacts 123 it provides a holding circuit for solenoid 125. With the lamps 117 and 1 19 lighted, the light is passed through the respective colored and light areas of the currency in the drawer. This light falling on the white, black and green cells 199a, 1991) and 1990, respectively, causes corresponding current to pass through the cells. In the case of the cells 199a, this current is extended through adjustable potentiometer 198a, contacts 185 and the winding of the associated meter relay 70. Current passing through cells 19911 extends through contacts 195 and the winding of the associated meter relay 80. Current passing through cells 1990 extends over contacts 191 and 181 through the winding of the associated meter relay 8-5. If light in more than a predetermined quantity is passed through respective areas of the currency, the respective cells pass suflicient current through the coils of the associated relays 70, 80 and/or 85 to close the associated contacts 71, 81 and 86.

If for any reason, such as an imperfect or counterfeit currency that passes too much light in one of the areas, closure of any of the contacts 71 or 86 connects one side of the secondary of transformer 20 extending through contacts 133 and conductor 134 to contacts 188 and/or contacts 183 to contacts 193 and the other side of the secondary of transformer 20 through the bad impulse relay 1'70. Contacts 81, if closed, connect conductor 134 to relay 170 through contact 193. On being connected across the secondary of transformer 20, relay 170 operates. This prevents any coin disposal, as will be explained.

Assuming that none of the aforementioned relays 70, 80 or 85 close their contacts, the next test will be conducted. As the rotor of motor 100 continues its operation, the contact 102 extends power from conductor 30 to conductor 40 through the first switch relay 180 and conductor 32 to energize switch relay 180.

This test is a determination that suflicient light passes the light and darkest areas of the bill to energize relays 160 and 150 respectively. At contacts 189', relay 180 locks operated through contacts 132. Relay 180 disconnects the contacts 86 and 7-1 from the bad impulse relay 170 at contacts 188 and 183 respectively. Instead, at contacts 189 and 184, respectively, it connects contacts 86 and 71 to relays 150 and 161!' respectively.' At contacts 18 5, the adjustable resistor or potentiometer 198 is disconnected from relay 70' and cells 199a connected directly to the winding of relay 70 at contacts 186. At contacts 187, positive potential from battery 166 is applied through adjustable resistor 167 and contacts 182 and 191 to permit relay to close its contacts in response to a predetermined light tvalue applied to cells 1990.

With the relay 70 connected directly across cells 199a and the booster battery applied to relay 85 and cells 199a, both relays close their contacts 71 and 81 respectively, responsive to the light passage. This connects the secondary of the 24-volt transformer through contacts 71 and 86, respectively, contacts 184 and 189, respectively, to relays 160 and 150 respectively. Both relays 150 and 169 therefore operate. If, on the other hand, contacts 71 or 86 fail to close, indicating the failure of the note to pass sufiicient light through either the white or black area of the note, payout will be prevented due to the failure of relays 150 and 160 to operate, as will be explained.

Relay'160 also locks operated through contacts 163 and at contacts 161 and 162 it prepares for currency stripping and coin payout respectively.

Relay 150 locks operated at contacts 153 and closes contacts 151 and 152to prepare for currency stripping and for coin payout.

With contacts 151 and 161 closed, a circuit is completed as soon as contact 102 on motor extends power from conductor 30 to conductor 42 over contacts 172, contacts 161 and contacts 151 to energize the stripper motor 145.

Stripper motor 145 closes contacts 146 to extend the power on conductor 30 through the stripper solenoid and the guillotine is operated as to strip the note from the slide drawer. It will be understood, of course, that a relay 'may first be energized to control the operation of the motor 145, solenoid 135 and relay through re spective contacts; however, for the purpose of illustration, or at any desired time in the cycle, contacts 148 close when the bill or note is stripped. This extends the power on conductor 30 through relay to initiate the tray clear test. It will be noted that the black cells 199s are used in conjunction with the green relay 80 to determine that removal has occurred. In the meantime, stripping the note from the slide opens switches 94 and 96; however, solenoid 125 is held operated over contacts 123.

Relay 190 locks operated through contacts 197, 189 and 132. At contacts 194, it connects the winding of the green test meter relay 80 through potentiometer 85a to one side of the black cells 199s, and at contacts 192 connects the windings of relays 80 to the other side of the cells 1990. At contacts 196, it connects the contacts 81 of relay 80 to the tray clear test relay 140. If the tray is clear, the winding of relay 80 is energized sufficiently to close contacts 81. This connects relay 140 across the secondary of transformer 20 to energize relay 140. Relay 140 looks operated over contacts 142 and closes contacts 141 to prepare the payout sequence. Of course, if relay 140 does not operate, payout will not occur, as will be explained.

The motor contact 102 coming in contact with conductor 43 after relay 140 is energized, extends power over contacts 173, 162, 152 and 141 to energize relay 110. Relay 110 operates to open contacts 111 and close contacts 112 and 113. Lights 117 and 119 extinguish when contact 101 disconnects from conductor 40.

Opening contacts 111 removes the DC. braking potential furnished by rectifier 12 in the output of transformer 6 and applied to the payout motor 14 to permit operation of the motor 14. The payout motor 14 now energizes over contacts 113.

As the payout motor operates, it extends a control arm or finger 14' into the coin chute to dispense coins as explained in the aforementioned application. With contacts 15 and 16 closed, indicating successful coin disposal, relay 110 and the payout motor 14 lock operated through contacts 112, 16 and 15 until the payout cycle is completed. This prevents restoration of motor 14 and relay 110 when contact 102 leaves conductor 43.

When arm 14' returns to normal to open contacts 15 and 16, contacts 15 and 16 on opening, of course open the holding circuits for relay 110 and motor 14 to restore them.

In the event a coin should jam to prevent the movement of the payout mechanism, contacts 15 and 16 remain open. The relay and motor are de-energized as soon as contact 102 leaves conductor 43. With contacts 21 thereafter failing to close, a later circuit is not completed to solenoid 125 and further tests are not conducted until the trouble is cleared.

As the rotor switch contact 101 comes in contact with conductor 45, power from conductor 30 is extended through contacts 123 to maintain the timer motor 189 operated. A moment later, when contact 102 connects power to conductor 44, the reset relay 130 energizes. Thus relay 130, on energizing, opens contacts 132 to open the circuit for start relay 12%) and that relay deenergizes. -At contacts 133, relay 130 restores operated relays 140, 150 and 160. At contacts 131, the original operating circuit for solenoid 125 is opened. With relays 140, 159 and 160 restored, the original circuit for payout motor 14 and relay 110 is restored. However, with switches 15 and 16 in their operated position, relay 110 and motor 14 continue operated, and on passing through the motor cycle and restoration of contacts 15 and 16, operation of the payout motor 14 and relay 110 is terminated. Relays 180 and 190 of course restore on the opening of their locking circuits. Relay 129 on restoring opens the holding circuit for solenoid 125 and it restores to release the slide which now returns to its normal position.

Assuming normal operation, the rotor contacts 161 and 102 pass from conductors 45 and 44 under control of motor 100. This terminates operation of the reset relay 130 and the timer motor 160, respectively, and the apparatus is now prepared for another cycle.

When the lock solenoid 125 is restored, the slide drawer is returned to its unoperated position. Switches 92, 94 and 96 therefore open.

In the event the bad impulse relay 170 was operated on any of the tests, circuits to stripper motor 145 and relay 190 or relay 110 cannot be completed as contacts 172 and 173 open. At contacts 171, relay 170 locks operated across contacts 133. Subsequent operation of the reset relay 130 restores the locking circuit for relay 17% and it restores.

In the event the relays 169 or 150 failed to operate responsive to the tests for sufiicient light passage, the circuits to motor 145, solenoid 135, and relays 190 or 110 cannot be completed as contacts 151, 152 or 161 and 162 remain open. Operation of the reset relay 130 thereafter releases the operated components as described.

If the tray clear test fails to operate relay 149, the circuit to relay 11%) cannot be completed as contacts 141 remain open. The DC brake on the payout motor 14 is maintained and therefore coin payout cannot take place. Thereafter, operation of the reset relay 130 restores the operated components asdescribed.

In accordance with the above, there has been shown and described herein an improved material or currency evaluation arrangement for improving the operation, testing and control by such evaluation arrangement, but the particular embodiments or forms of the invention described herein are not limitations upon other manners of practicing the invention.

It will be understood that the concepts of this invention will have application also to the testing of other sheet material having an imprint, color or design on the sur faces thereof or embodied therein whereby the reaction to light will vary in accordance with the particular patterns.

It will be further understood that other changes in the details of construction, arrangement and operation may 1. A currency testing arrangement for determining the validity of a currency note having a plurality ofdilfen, ently colored areas, comprising means for passing light through the darkest area of said note, means thereafter controlled responsive to more than a predetermined maximum amount of light passing through said dark area for determining said note is invalid, and means controlled responsive to less than a predetermined minimum amount of light passing through said dark area for determining said note invalid.

2. The arrangement claimed in claim 1 in which both controlled means include light-responsive cell means.

3. In the arrangement claimed in claim 2, means for increasing the response level of at least a portion of said cell means to determine the passage of less than a predetermined minimum amount of light.

4. In the arrangement claimed in claim 3, means to increasing said response level at a predetermined time.

5. The arrangement claimed in claim 3 in which the increasing means comprises a booster battery.

6. A currency testing arrangement for determining the validity of a currency note having a plurality of areas which have varying degrees of light transmittance com prising, means for passing light through said note, photoresponsive means individual to at least certain of said note areas, means operated by said respective photoresponsive means on the passage of more than a predetermined minimum amount of light through a relatively low light transmitting note area to give an indication that said note is valid, and means controlled by said respective photo-responsive means if more than a predetermined maximum amount of light passes through said relatively low light transmitting note area to give an indication that said note is invalid.

7. A currency testing arrangement for determining the by said respective photo-responsive means if more than a predetermined maximum amount of light passes through the dark area for determining that said note is invalid.

8. A currency testing arrangement for determining the validity of a currency note having a plurality of differently colored areas comprising, means for passing light rays through a dark area of said note, means responsive to the passage of more than a predetermined minimum of light rays through said dark area to give an indication that the note is valid, and means responsive to the passage of more than a predetermined maximum amount of light rays through said dark area to give an indication that said note is invalid.

9. A currency testing method for determining the validity of a currency note having a plurality of areas which have varying degrees of light transmittance, comprising the steps of transmitting light through at least a relatively low light transmitting area of the note, testing that the amount of light transmitted through said note area exceeds a predetermined minimum limit, testing that the amount of light transmitted through said note area is less than a predetermined maximum limit, and accepting said note as valid only if the amount of light transmitted through said note area falls within said limits.

10. A currency testing method for determining the validity of a currency note having a pluralityof relatively dififerent colored areas, comprising the steps of transmitting light through at least a relatively dark area of said note, testing that the amount of light transmitted, through said relatively dark area exceeds a predetermined minimeans for determining the passage of more than said mum limit, testing that the amount of light transmitted predetermined minimum amount of lightthrough said relatively dark area is less than a predeter- References Cit d i h fil f hi patent mined maximum limit, and accepting said note as valid 5 UNITED STATES PATENTS only if the amount of 11g n-. t1ansm1ttcd through stud r l 2,381,505 Li H dh 01 m Aug. 7, 1945 W611i dal'k fireafal s ll'l 53 l 2 01 343 Johnson July 30 57 11. The arrangement claimed in claim 7 in which said 2,922,393 Eu Jan 1960 dark area is marked with black color. 2,950,799 Ti Aug, 30, 19 0 12. In the arrangement claimed in claim 7, means for 10 2,957,387 Patzer Oct. 25, 1960 increasing the response level of said respective responsive 2,967,452 PatZcr I an. 10, 1961 

7. A CURRENCY TESTING ARRANGEMENT FOR DETERMINING THE VALIDITY OF A CURRENCY NOTE HAVING A PLURALITY OF RELATIVELY DIFFERENT COLORED AREAS COMPRISING, MEANS FOR PASSING LIGHT THROUGH SAID NOTE, PHOTO-RESPONSIVE MEANS INDIVIDUAL TO EACH DIFFERENTLY COLORED AREA OF SAID NOTE, MEANS OPERATED BY SAID RESPECTIVE PHOTO-RESPONSIVE MEANS ON THE PASSAGE OF MORE THAN A PREDETERMINED MINIMUM AMOUNT OF LIGHT THROUGH A DARK AREA OF SAID NOTE TO GIVE AN INDICATION THAT SAID NOTE IS VALID, AND MEANS CONTROLLED BY SAID RESPECTIVE PHOTO-RESPONSIVE MEANS IF MORE THAN 